Several drone incidents over the past year have highlighted tension in the Gulf as Iran
and the United States flex their military capabilities in the vital oil exporting region in a standoff over Iran's disputed nuclear program.

The lightweight RQ11 Raven drones were brought down by Iranian air defense units in separate incidents in August 2011 and November 2012, Rear Admiral Amir Rastegari told the Fars news agency.

"Much of the data of these drones has been decoded by the Army's jihad and research centre," he said, without elaborating.

Manufactured by AeroVironment, the RQ11 Raven has a wingspan of 4.5 feet and a range of 6.2 miles and is used by the US
military for low-altitude surveillance.

Iran said on December 4 that it had captured a US intelligence ScanEagle
drone in its air space over the Gulf in the previous few days, but the United States said there was no evidence to support the assertion.

The US Navy said had not lost any unmanned aircraft in the area.

In November, the United States said Iranian warplanes shot at a US drone flying in international air space.

Iran said the aircraft had entered its air space to spy on Iranian oil platforms and said it would respond "decisively" to any incursions.